The Rogness OST Porter I mentioned above is from Pfugerville, TX and is pretty good. Has a bitter back-end which I like but might not be for everybody.

I also enjoy Anchor Porter, Sierra Nevada Porter, Breckinridge Vanilla Porter, Stone Smoked Porter, Boulevard Bully! Porter, and Leinenkugel Snowdrift Vanilla Porter. Those are ones that I've enjoyed that can be found relatively easily in Central Texas (well maybe not Bully! but the others might be available in Lubbock).

Sam Adams makes a good maple pecan porter (not sure of availability). If you ever make it out to Denver, Denver Beer Co makes a kick-ass Graham Cracker Porter (medaled at GABF). Mountain Sun Brewery does a killer Java Porter as well.